The invention relates to an apparatus for supplying powder onto a plane surface of a device for creating a three-dimensional part in a layer-by-layer fashion according to the pre-characterizing part of claim 1.
Devices for creating a three-dimensional part in a layer-by-layer fashion are known for example from WO 95/18715, WO 98/18124 and from EP 0 882 568. Using such devices, a three-dimensional part is created by selectively solidifying successive layers of a powdery material at locations corresponding to the respective cross section of the part, for example by the action of a laser beam.
In a known device of this type, in each lateral end position, a predetermined amount of powder from a store container is entered into a covering apparatus. In order to make sure that in each layer the entire surface is reliably covered with powder, the predetermined amount has to be larger than the amount theoretically required. Due to non-uniform sintering in each of the previous layers as regarded across the width of the surface, powder consumption in individual sections of the covering apparatus is different. For that reason, prior to the subsequent filling or after a predetermined number of covering processes, the covering apparatus is emptied across its entire width before a new filling with a predetermined amount of powder across the entire width is carried out. On the one hand, this causes a relatively high powder consumption and the powder has to be recycled. On the other hand, the overall process is extended by the required emptying process.
A device where the predetermined amount of powder filled into the covering means is larger than the amount theoretically needed and where the excessive powder is emptied after each covering process, is known from WO 95/18715.
It is an object of the invention to avoid the above described drawbacks.
This object is achieved by the apparatus characterized by the features of claim 1.